CN105784839A - Method for detecting micro-defects on surfaces of metal container - Google Patents
Method for detecting micro-defects on surfaces of metal container Download PDFInfo
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- CN105784839A CN105784839A CN201610160850.7A CN201610160850A CN105784839A CN 105784839 A CN105784839 A CN 105784839A CN 201610160850 A CN201610160850 A CN 201610160850A CN 105784839 A CN105784839 A CN 105784839A
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- coil
- excitation coil
- magnetoresistive transducer
- detection device
- exciting coil
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/72—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables
- G01N27/82—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws
- G01N27/90—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating magnetic variables for investigating the presence of flaws using eddy currents
Abstract
The invention discloses a device for detecting micro-defects on the surfaces of a metal container. The device is characterized by comprising an alternating-current power source (1), a phase-locked amplifier (2), an exciting coil (3), a demagnetizing coil (4), a magnetic resistance sensor (5), an oscilloscope (6), pulleys (8), a first movable support (9), a second movable support (10), a fixed support (11) and a base (12); the diameter of the exciting coil (3) is 800 mm, the diameter of the demagnetizing coil (4) is 10 mm, and the diameters of copper wires are 0.2-2 mm; two signals can be generated by the alternating-current power source (1) and are respectively applied to the exciting coil (3) and the demagnetizing coil (4), magnetic fields can be generated in spaces by the exciting coil (3) by means of excitation, the spatial magnetic fields can be changed under the effects of the defects on the surfaces of the to-be-detected metal container (7), change of the spatial magnetic fields can be detected by the magnetic resistance sensor (5), the demagnetizing coil (4) is used for weakening influence of the spatial magnetic fields, which are generated by the exciting coil (3) by means of excitation, on the magnetic resistance sensor (5), and detection signals of the magnetic resistance sensor (5) can be amplified by the phase-locked amplifier (2) and then can be displayed by the oscilloscope (6). The device has the advantages of high penetration depth, simplicity and convenience in operation, low cost and the like. Besides, the device can be applied to different types of actual engineering.
Description
Technical field
A kind of metal vessel surface tiny flaw detection device, belongs to electromagnetic nondestructive field.
Background technology
According to a large amount of about large-scale storage tank, the statistical analysis of pipeline accident case, fire disaster, explosion accident are the most all by one
Consecutive minor accident superposition causes, and some fine cracks that the sign of these minor accident early stages occurs often caused by equipment cause
Caused by fuel, crude oil leakage.If in early days these fine cracks can be made detection, it is unnecessary to avoid undoubtedly causing
Life and property loss.
Eddy detection technology is the main Dynamic Non-Destruction Measurement of existing one, during traditional single-frequency EDDY CURRENT, exists very
Many interference and influence factor (magnetic conductivity, electrical conductivity, appearance and size and various defect).For getting rid of other disturbing factors further,
Improve the recognition capability of defect, progressively develop multifrequency Eddy, impulse eddy current, far-field eddy, alternative current field measurement, eddy current
The technological means such as array.Conventional eddy current is usually 1KHz-500KHz, is affected by Kelvin effect, wearing of EDDY CURRENT
Thoroughly the degree of depth is limited significantly, and therefore EDDY CURRENT is usually used in metal surface and near surface detection, this greatly limits current boiler,
The accuracy of detection of the pressure-bearing class special equipments such as pressure vessel and piping and detection range.
Summary of the invention
It is an object of the invention to provide a kind of metal vessel surface tiny flaw detection device.This device can to large-scale storage tank,
The equipment such as petroleum pipeline, boiler carries out on-line checking.There is the features such as accuracy of detection height, fast response time, penetration depth be deep.
The present invention is achieved through the following technical solutions:
A kind of metal vessel surface tiny flaw detection device, it is characterised in that: by AC power (1), lock-in amplifier (2),
Excitation coil (3), anti-magnetized coil (4), magnetoresistive transducer (5), oscillograph (6), pulley (8), the first movable supporting frame (9), second
Movable supporting frame (10), fixed support (11), base (12) form；Wherein a diameter of 800mm of excitation coil (3), anti-magnetized coil
(4) a diameter of 10mm, copper wire diameter is 0.2-2mm；AC power (1) produces two signals and is respectively applied to excitation coil (3)
With on anti-magnetized coil (4), excitation coil (3) inspires magnetic field in space, and the defect on tested canister (7) surface can make space magnetic field
Changing, magnetoresistive transducer (5) can detect that this change, anti-magnetized coil (4) are used for weakening the space magnetic that excitation coil (3) excites
The field impact on magnetoresistive transducer (5), the detection signal of magnetoresistive transducer (5) amplifies again by oscillograph (6) via lock-in amplifier (2)
Show.
Described a kind of metal vessel surface tiny flaw detection device, it is characterised in that: the frequency of AC power (1) output signal
For 1-50Hz.
Described a kind of metal vessel surface tiny flaw detection device, it is characterised in that: magnetoresistive transducer is apart from test specimen table to be measured
Face 0.1-1mm.
Described a kind of metal vessel surface tiny flaw detection device, it is characterised in that: excitation coil (3) and anti-magnetized coil (4)
At a distance of 500-530mm.
The operation principle of the present invention is: the low-frequency ac signal that AC power (1) produces is applied to excitation coil (3) and anti-magnetized coil (4)
On, excitation coil (3) inspires alternating magnetic field in space, and anti-magnetized coil (4) is used for weakening excitation coil (3) to magnetoresistive transducer (5)
Impact, owing to vary through the magnetic flux of tested canister (7) constantly, so the surface of canister (7) has eddy current and goes out
Existing, when discontinuous defect occurs in canister (7) surface, the flow direction of eddy current can be made to change, thus cause vortex excitation
Magnetic field also changes, and magnetoresistive transducer (5) senses this change, and is led to via after lock-in amplifier (2) amplification by detection signal
Cross oscillograph (6) to show.
The invention has the beneficial effects as follows: should have penetration depth deeply by defect detecting device based on low frequency eddy current, detection speed is fast,
Without surface of test piece being carried out the features such as pretreatment.Additionally, the anti-magnetized coil of described device (4) can protect magneto-resistive transducing well
Device (5) is from the interference of excitation coil (3) so that magnetoresistive transducer (5) has higher precision to the detection of defect.
Accompanying drawing explanation
Fig. 1 is a kind of metal vessel surface tiny flaw detection device schematic diagram of the present invention；
Fig. 2 is the testing result schematic diagram of the different-thickness test specimen of the present invention；
Detailed description of the invention
Below in conjunction with the accompanying drawings and embodiment the invention will be further described:
See accompanying drawing 1, a kind of metal vessel surface tiny flaw detection device: by AC power (1), lock-in amplifier (2),
Excitation coil (3), anti-magnetized coil (4), magnetoresistive transducer (5), oscillograph (6), pulley (8), the first movable supporting frame (9), second
Movable supporting frame (10), fixed support (11), base (12) form；AC power (1) produces two signals and is respectively applied to encourage line
On circle (3) and anti-magnetized coil (4), excitation coil (3) inspires magnetic field in space, and the defect on tested canister (7) surface can make sky
Between magnetic field change, magnetoresistive transducer (5) can detect that this change, anti-magnetized coil (4) are used for weakening what excitation coil (3) excited
The space magnetic field impact on magnetoresistive transducer (5), the detection signal of magnetoresistive transducer (5) amplifies again by showing via lock-in amplifier (2)
Ripple device (6) shows.
Wherein, anti-magnetized coil (4) can weaken the excitation coil (3) impact on magnetoresistive transducer (5).Fig. 2 is different-thickness test specimen
Testing result schematic diagram.
Claims (4)
1. metal vessel surface tiny flaw detection device, it is characterised in that: by AC power (1),
Lock-in amplifier (2), excitation coil (3), anti-magnetized coil (4), magnetoresistive transducer (5), oscillograph (6),
Pulley (8), the first movable supporting frame (9), the second movable supporting frame (10), fixed support (11), base (12)
Composition；Wherein a diameter of 800mm of excitation coil (3), a diameter of 10mm of anti-magnetized coil (4), copper
Linear diameter is 0.2-2mm；AC power (1) produces two signals and is respectively applied to excitation coil (3) and disappears
On magnetic coil (4), excitation coil (3) inspires magnetic field, the defect on tested canister (7) surface in space
Space magnetic field can be made to change, and magnetoresistive transducer (5) can detect this change, and anti-magnetized coil (4) is used
In weakening the impact on magnetoresistive transducer (5) of space magnetic field that excitation coil (3) excites, magnetoresistive transducer (5)
Detection signal amplify via lock-in amplifier (2) and shown by oscillograph (6) again.
A kind of metal vessel surface tiny flaw detection device the most according to claim 1, its feature
It is: the frequency of AC power output signal is 1-50Hz.
A kind of metal vessel surface tiny flaw detection device the most according to claim 1, its feature
It is: magnetoresistive transducer (5) is 0.1-1mm apart from surface of test piece to be measured.
A kind of metal vessel surface tiny flaw detection device the most according to claim 1, its feature
It is: excitation coil (3) and anti-magnetized coil (4) are at a distance of 500-530mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610160850.7A CN105784839A (en) | 2016-03-18 | 2016-03-18 | Method for detecting micro-defects on surfaces of metal container |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610160850.7A CN105784839A (en) | 2016-03-18 | 2016-03-18 | Method for detecting micro-defects on surfaces of metal container |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN105784839A true CN105784839A (en) | 2016-07-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201610160850.7A Pending CN105784839A (en) | 2016-03-18 | 2016-03-18 | Method for detecting micro-defects on surfaces of metal container |
Country Status (1)
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| CN (1) | CN105784839A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106596713A (en) * | 2016-11-23 | 2017-04-26 | 电子科技大学 | Nondestructive testing probe system with high signal-to-noise ratio |
| CN106932472A (en) * | 2017-03-05 | 2017-07-07 | 北京工业大学 | A kind of two-way excitation eddy current sensor of magnetic screen type |
| CN108008005A (en) * | 2017-12-28 | 2018-05-08 | 中国特种设备检测研究院 | A kind of metallic conduit defects detection low frequency electromagnetic flexible array sensor |
| CN110057665A (en) * | 2019-04-24 | 2019-07-26 | 三峡大学 | It is a kind of by surface micro-strain amplificationization and visible apparatus and method |
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| JPS58147662A (en) * | 1982-02-26 | 1983-09-02 | Shimadzu Corp | Measuring device for eddy current magnetic field of ship's hull |
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| JPH07311180A (en) * | 1994-05-19 | 1995-11-28 | Hitachi Cable Ltd | Eddy current flaw detection coil |
| CN102183579A (en) * | 2011-02-21 | 2011-09-14 | 南京农业大学 | Eddy current testing probe |
| CN202994725U (en) * | 2012-12-06 | 2013-06-12 | 天津赛瑞机器设备有限公司 | Defect detecting coil device |
| CN103822967A (en) * | 2014-03-18 | 2014-05-28 | 江苏理工学院 | Automatic dual-exciting-coil conductor defect flaw detection device and method |
| CN104730144A (en) * | 2015-02-10 | 2015-06-24 | 中国人民解放军海军航空工程学院青岛校区 | Eddy-current transducer for detecting internal corrosion of multilayer structure and manufacture method of eddy-current transducer |
| CN105353030A (en) * | 2015-12-08 | 2016-02-24 | 中国计量学院 | Low-frequency electromagnetism-based defect detecting device |
| CN205643250U (en) * | 2016-03-18 | 2016-10-12 | 中国计量学院 | Small defect detecting device in metal container surface |
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2016
- 2016-03-18 CN CN201610160850.7A patent/CN105784839A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58147662A (en) * | 1982-02-26 | 1983-09-02 | Shimadzu Corp | Measuring device for eddy current magnetic field of ship's hull |
| JPS61264251A (en) * | 1985-05-17 | 1986-11-22 | Hitachi Metals Ltd | Eddy current flaw inspecting method and its device |
| JPH07311180A (en) * | 1994-05-19 | 1995-11-28 | Hitachi Cable Ltd | Eddy current flaw detection coil |
| CN102183579A (en) * | 2011-02-21 | 2011-09-14 | 南京农业大学 | Eddy current testing probe |
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| CN103822967A (en) * | 2014-03-18 | 2014-05-28 | 江苏理工学院 | Automatic dual-exciting-coil conductor defect flaw detection device and method |
| CN104730144A (en) * | 2015-02-10 | 2015-06-24 | 中国人民解放军海军航空工程学院青岛校区 | Eddy-current transducer for detecting internal corrosion of multilayer structure and manufacture method of eddy-current transducer |
| CN105353030A (en) * | 2015-12-08 | 2016-02-24 | 中国计量学院 | Low-frequency electromagnetism-based defect detecting device |
| CN205643250U (en) * | 2016-03-18 | 2016-10-12 | 中国计量学院 | Small defect detecting device in metal container surface |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106596713A (en) * | 2016-11-23 | 2017-04-26 | 电子科技大学 | Nondestructive testing probe system with high signal-to-noise ratio |
| CN106932472A (en) * | 2017-03-05 | 2017-07-07 | 北京工业大学 | A kind of two-way excitation eddy current sensor of magnetic screen type |
| CN108008005A (en) * | 2017-12-28 | 2018-05-08 | 中国特种设备检测研究院 | A kind of metallic conduit defects detection low frequency electromagnetic flexible array sensor |
| CN110057665A (en) * | 2019-04-24 | 2019-07-26 | 三峡大学 | It is a kind of by surface micro-strain amplificationization and visible apparatus and method |
| CN110057665B (en) * | 2019-04-24 | 2021-08-24 | 三峡大学 | Device and method for amplifying and visualizing surface micro deformation |
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Application publication date: 20160720 |